There are around a thousand different crypto currencies floating around at the moment. They all operate a bit different from each other. They’re each trying to establish themselves as occupying some niche purpose.
It’s best to judge each one according to the niche it occupies.
Bitcoin, the original or gen 1 crypto currency, after much community dispute resolution, looks like being a lower transaction rate, higher value. Think of it like digital gold bullion. You don’t buy a coffee with bars of gold.
Chicago Mercantile Exchange just opened a futures market for Bitcoin. That’s about as real as it gets in finance markets.
Ethereum, a gen 2 crypto currency, operates on proof of stake rather than proof of work, so doesn’t have the massive overheads of Bitcoin, though it still seems to have scaling issues (as recently revealed by “crypto kitties” - look it up). It’s also functions as a programming language on the block chain, enabling fully distributed executable business agreements as code. This is a huge deal, but with much complexity to resolve over time.
IOTA is a gen 3 crypto currency. It doesn’t even use block chain, instead using a new system called a Tangle. It has zero transaction fees, open ended scale-ability with linear increasing capacity as nodes are added. It’s niche is microtransactions suitable for internet-of-things scale activity. As little heard of as it may be to you, it currently has a market capitalisation of around $15 Billion.
The banks have their own thing because they want to oust their own middle man in the form of Swift. Last I heard, that’s probably Ripple.
The collective stock exchanges of the world own their own settlement agent, who announced about a year ago that they were making their own block chain solution for inter exchange settlement, “before someone else does”.
Oh, and forgot to mention what you might actually buy your coffee with. Likely candidates look like Litecoin or Bitcoin-Cash (forked off the original Bitcoin in August).
PPAU should also consider the privacy gains possible in crypto currency as it opposed government trends toward eliminating cash , thereby increasing the resolution of their surveillance of every damned thing we do.